In-depth Understanding of 2SA1943 PNP Power Transistor
26 January 2024
Ⅱ. 2SA1943 symbol, footprint and pin configuration
Ⅳ. Absolute maximum ratings of 2SA1943
Ⅴ. How does 2SA1943 transistor realize high collector current?
Ⅵ. How to use 2SA1943 PNP power transistor?
Ⅶ. How to test the 2SA1943 transistor good or bad?
2SA1943 is a PNP high-voltage power transistor widely used in audio power amplifiers, DC-DC converters and other high-power circuits. In this article, we will delve into the details of the 2SA1943 transistor, explore its applications and usage, and more. Whether you are an electronics enthusiast or professional, this guide is designed to give you a comprehensive understanding of the 2SA1943 power transistor.
The 2SA1943 is a 30MHz frequency transistor that plays a key role in amplifier design. Generally speaking, power amplifiers mostly use the same push-pull circuit as class B power amplifiers. This kind of power amplifier can be constructed with two transistors, such as PNP and NPN. Among them, the 2SA1943 transistor is a PNP type, while the 2SE5200 is an NPN transistor. Therefore, we often use a combination of these two transistors to design high-power amplifiers. This type of power transistor is made of semiconductor material and usually has at least three terminals for connecting to external circuits. When current or voltage is applied to one pair of terminals of this transistor, it controls the flow of current in the other pair of terminals because the output power is higher than the input power.
When these transistors are operated at high collector current and maximum switching frequency, they heat up rapidly. So to avoid thermal issues we better use a heat sink. These PNP power transistors are suitable for stereo systems designed with a power of 200W or higher, a frequency range of 5Hz to 100kHz, and a sensitivity of 0.75Vrms. Additionally, the low signal-to-noise ratio and total harmonic distortion make these transistors particularly suitable for audio-related applications.
Alternatives and equivalents:
• 2SA1962
• KTA1962
• TTA1943
• TTC5200
• MJW1302A
The following figures show the symbol, footprint and pin configuration of 2SA1943. Among them, it has three pins, below is its name and description.
Pin 1 (Base): The base terminal is the trigger for the transistor.
Pin 2 (Collector): Current flows through the collector.
Pin 3 (Emitter): Current flows through the emitter.
• Professional audio equipment: Due to its high power and audio quality, 2SA1943 is also widely used in professional audio equipment such as studio monitor amplifiers and performance sound systems. These equipments have very high requirements on audio processing, and the outstanding performance of 2SA1943 makes the sound of professional audio equipments more pure and delicate. Therefore, this power transistor becomes one of the important choices for professional audio equipment.
• Power amplifier module: 2SA1943 can be used to make stand-alone power amplifier modules, which can be used for various applications such as DIY sound systems or other audio equipment. This power transistor has a high output capability and low input resistance, so it can provide better power amplification.
• Audio power amplifier: 2SA1943 transistor is commonly used as an output transistor for high power audio amplifier circuits. These power amplifiers have a wide range of applications in home audio systems, professional audio equipment, and stage amplifiers. They are capable of amplifying weak audio signals into sound powerful enough to power a wide range of audio equipment.
• Audio system: This transistor is usually used to build the output stage of an audio amplifier to provide sufficient power and sound quality. This is because of the 2SA1943's excellent sound quality and powerful output capability, which makes it the first choice for many professional and amateur audio enthusiasts.
• Amplifier design: The 2SA1943 is often used with its NPN-type complementary transistor, the 2SC5200, to form a push-pull amplifier circuit. Push-pull amplifier circuits are a common type of amplifier circuit with high power output and low harmonic distortion. This circuit structure is commonly used in audio amplification, power amplification, etc.
• Audio amplifier boards: This transistor is often integrated into audio amplifier boards. These boards are specially designed to be used in the assembly of audio power amplifiers, and they provide a convenient platform for producers to make building high-performance audio systems easier. By using these boards directly for assembly, producers can quickly build audio power amplifiers that meet specific needs and can ensure consistent and reliable system performance.
Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even if the operating conditions (i.e.operating temperature/current/voltage, etc.) are within the absolute maximum ratings. Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook ("Handling Precautions"/Derating Concept and Methods) and individual reliability data (i.e. reliability test report and estimated failure rate, etc).
The power supply is applied to the emitter junction, causing the emitter junction to be forward biased. This induces free electrons in the emitter region to flow to the base region, resulting in an emitter current. As free electrons accumulate near the emitter junction, an electron concentration difference is formed within the base region as the number of free electrons in the region increases. This results in a gradual flow of free electrons from the emitter junction to the collector junction, which results in the formation of a collector current. Since the collector junction is subjected to a large reverse voltage, it effectively prevents the free electrons in the collector region from diffusing into the base region and attracts the free electrons that have gathered in the vicinity of the collector junction to the collector region, resulting in the formation of a collector current.
An amplifier circuit using three transistors is shown below. The components required to build this circuit mainly include three transistors, such as 2SC5200 (NPN), 2SA1943 (PNP) and BD139 (NPN). Two D1 and D2 diodes like Diode 1N4007, electrolytic capacitors like C1 is 2.200uF to 63V, C2 is 4.7V, resistors like R1 and R2 are 0.22 ohm, 5W, 1K ohm resistor, 100K resistor, 10K ohm potentiometer, connections Line etc. The circuit is designed to be very simple and can drive a 600W RMS subwoofer speaker using three transistors. The testing of this circuit can be completed in two stages, in which the first stage uses an asymmetric power supply of 24V and the second stage uses an asymmetric power supply of 30V.
The primary stage is called the preamplifier stage and is also used to enhance the output stage. Class H can be constructed from medium-power BD139 transistors, supporting up to 80 volts, 1.5 amps and 12.5 watts. The second stage is called the power stage, which can be formed by NPN and PNP complementary transistors such as the 2SC5200 and 2SA1943, with high fidelity, 100 watts of power and 15 A collector current. If we want to use any amplifier circuit with 20 volts or more then we have to use power transistor with heat sink and the amplifier is used continuously. However, these transistors heat up quickly during use.
To check if the 2SA1943 transistor is working, we need to use a multimeter to perform a continuity check. First, we turn on and set the multimeter to continuity checker mode. We place the 2SA1943 on the workbench and connect the positive and negative leads of the multimeter to any two adjacent terminals of the 2SA1943. Repeat this process for all possible combinations of the two ends of the transistor. For the 2SA1943 transistor, we need to pay attention to the connection method of its PN junction. The tube has three PN junctions, namely the emitter junction, the collector junction and the base. During the inspection process, we need to ensure that the multimeter's test leads and PN junction are connected correctly, and at the same time ensure that the multimeter's gear setting is correct. If the multimeter makes a sound indicating continuity or a short circuit between the transistor terminals, then we should replace the 2SA1943 transistor with a new one.
Frequently Asked Questions
1. What is the primary application of the 2SA1943 transistor?
The 2SA1943 is often used in high-power audio amplifier circuits due to its ability to handle large current and power loads.
2. What is the use of 2SA1943 transistor?
The 2SA1943 is a high power PNP transistor originally from Toshiba. Due to its high current gain and collector current, it is very commonly used in High power audio circuits or AF amplifiers.
3. What is the difference between TTA1943 and 2SA1943?
TTA1943 and 2SA1943 differ primarily in DC current gain and collector output capacitance. TTA1943 and 2SA1943 have minimal hFEs of 80 and 55, respectively. TTA1943 and 2SA1943 have COBs of 240 pF and 360 pF, respectively.
4. How does a PNP transistor work?
In a PNP transistor, the base current which enters into the collector is amplified. The flow of current is typically controlled by the base. Current flows in the opposite direction in the base. In a PNP transistor, the emitter emits “holes”, and these holes are collected by the collector.
